Limit stop mechanism for gun turrets



Feb. 26, 1952 w. E. NAUGLER EIAL 2,586,982

LIMIT STOP MECHANISM FOR GUN TURRETS L J inventors WaZterE/Va ugler Ernes t W Stacey 15 Sheets-Sheet 55 W. E. NAUGLER ETAL LIMIT STOP MECHANISM FOR GUN TURRETS Feb. 26, 1952 Filed June 1, 1948 Feb. 26, 1952 w. E. NAUGLER ETAL 2,586,982

I LIMIT STOP MECHANISM FOR GUN TURRETS Filed June 1, 1948 15 Sheets-Sheet 4 Inventors WcilzerE/Vaugler Ernest W. Stacey Biy z'rAzzo'rney Feb. 26, 1952 w. E. NAUGLER ETAL LIMIT STOP MECHANISM FOR GUN TURRETS 15 Sheets-Sheet 5 Filed June 1, 1948 Inventors Walter E. Naugler 15 Sheets-Sheet 6 5 S w y r 9 w 0 u m w m f a S m N m6 vEW. n r m Owm I M n ww u /Qmn W 5 .WRM mm D 0 o, m m m mm I f |11F| nu mu wk w. u ,HC f t) D Feb. 26, 1952 w. E. NAUGLER ETAL LI'MIT STOP MECHANISM FOR GUN TURRETS Filed June 1, 1948 1952 w. E. NAUGLER ETAL 2,586,982

LIMIT STOP MECHANISM FOR GUN TURRETS Filed June 1, 1948 15 Sheets-Sheet 'r fnverzfors WaZzerE/Vaugler Ernest WSzac'ey Feb. 26, 1952 W. E. NAUGLER EI'AL LIMIT STOP MECHANISM FOR GUN I URRETS Filed June 1, 1948 eejas-Sheet 8 Feb. 26, 1952 w. E. NAUGLER ETAL LIMIT STOP MECHANISM FOR GUN TURRETS l5 Sheets-Sheet 9 Filed June 1, 1948 I-lll 15 Sheets-Sheet 10 W. E. NAUGLER ETAL LIMIT STOP MECHANISM FOR GUN TURRETS Feb. 26, 1952 Filed June 1, 1948 Feb. 26, 1952 w. E. NAUGLER ETAL 86,

LIMIT STOP MECHANISM FOR GUN TURRETS Filed June 1, 1948 15 Sheets-Sheet 11 0 15 Inventors aZzerENau gler Ernest WSfac'ey B 2 e 474 51 H 9 1952 w. E. NAUGLER EI'AL Y LIMIT STOP MECHANISM FOR.GUN TURRETS l5 Sheets-Sheet 12 Filed June 1, 1948 Inventors WczZzerENaugZer Feb. 26, 1952 w. E. NAUGLER EI'AL LIMIT STOP MECHANISM FOR GUN TURRETS l5 Sheets-Sheet 15 Filed June 1, 1948 15 Sheets-Sheet 14 mmm v m 1 AN. %\h R 0 9 a NNV W? WWW m w& Z N Q W 2g sum h v x $22. J \W1'\- n r s m? wk l me am a r W E Feb. 26, 1952 w. E. NAUGLER ETAL LIMIT STOP MECHANISM FOR GUN TURRETS Filed June 1, 1948 Feb. 26, 1952 w. E. NAUGLER EIAL LIMIT STOP MECHANISM FOR GUN TURRETS Filed June 1, 1948 15 Shegts-Sheet l5 U i m qm W WW lww m W E 6 0 Svm zozzo Patentecl Feb. 26, 1952 LIMIT STOP MECHANISM FOR GUN TURRETS Walter E. Naugler and Ernest W. Stacey, Beverly,

Mass., assignors to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey 7 Application June 1, 1948, Serial No. 30,328

1 Claim. 1

This invention relates to ordnance and is illustrated as embodied in an armed mount of the general type disclosed in an application for United States Letters Patent Serial No. 707,216, filed November 1, 1946 in the names of Ernest W. Stacey et al., patented February 20, 1951, as Patent No. 2,542,217, it being an object of the invention to provide an improved armed mount which may be used efiectively in long range aircraft.

The present invention consists in novel features hereinafter described, reference being had to the accompanying drawings which show one embodiment of the invention selected for purposes of illustration, and said invention being fully disclosed in the following description and claim.

In the drawings,

Fig. l is a side view, partly broken away, of the illustrative armed turret;

Fig. 2 is a section on line II-II of Fig. 1;

Fig. 3 is a rear view of hand grip control mechanism, partly broken away. which is located in a gunners compartment shown in Figs. 1 and 2;

Fig. 4 is a plan View of portions of the mechanism illustrated in Fig. 3, part of said view being taken on line IVIV of Fig. 3;

Fig. 5 is a view on line V-V of Fig. 3;

Fig. 6 is a side elevation, partly broken away and partly in section, of portions of an azimuth drive and limit stop and fire interrupter mechanism;

Fig. 7 is a section on line VII-VII of Fig. 6;

Fig. 8 shows in side elevation portions of mechanism for driving the turret in elevation;

Fig. 9 is a section on line IXIX of Fig 8;

Fig. 10 shows in side elevation portions of the azimuth drive, an aided tracking box and portions of mechanism for automatically limiting movement of the turret in elevation;

Fig. 11 is an enlarged view, partly broken away, showing in detail the elevation limit stop mechanism;

Fig. 12 shows a section Fig. 1;

Fig. 13 shows a section on line XIIIXIII of Fig. 12;

Fig. 14 is an enlarged view on line XIV-XIV of Fig. 7;

Fig. 15 is a section on line XVXV of Fig. 6;

Fig. 16 is a view, partly in section, showing on an enlarged scale portions of the azimuth drive;

on line XII-XII of Fig. 17 is a plan view of a portion of mechanism.

for manually operatingthe turret in azimuth when the power is off;

Fig. 18 is a schematic view showing in perspective portions of the mechanism for driving and controlling movement of the turret; and

Fig. 19 is a turret wiring control diagram.

An illustrative turret 30, best shown in Figs. 1 and 2, has a support ring 32 to which are secured four nuts 34 in threaded relation with screws 36 rotatably mounted in housings 38 (Fig. 1) (only two shown) forming part of a fuselage of an airplane. The screws 36 are rotated at the same speed by mechanism operated by an electric motor (not shown) Whichis controlled either from the outside of the turret or from the inside of the fuselage. By mounting the support ring 32 on the screws 36, the turret ma be quick-- ly and effectively raised to a retracted position inside the fuselage or may be projected to a firing position below the belly of the fuselage. Since the mechanism for supporting the turret 30 and for moving it to and from its firing position is substantially identical with mechanism for operating the turret disclosed in said Patent No. 2,542,217, such mechanism will not be described herein in detail.

The turret 30 has secured to its receivers 39 (Fig. 2) of a pair of 37 mm. guns 40 which are disposed at opposite sides, and extend outside of a gunners compartment 42 (Figs. 1, 2 and 17) and are automatically supplied with ammunition by feeders 44 (Fig. 2) secured to and arranged inside the turret. Chargers 46 controlled by cranks 48, 48a (Figs. 1, 2, 17 and 18) rotatably mounted in side walls 50, 50a of the gunners compartment 42 of the turret 30 are also provided. The ammunition feeders 44 from the subject-matter of an application for United States Letters Patent Serial No. 637,236, filed December 26, 1945, in the names of Ernest W. Stacey and Frank W. Reinhold, patented January 17, 1950, as Patent No. 2,494,728, and the chargers 46 form the subject-matter of an application for United States Letters Patent Serial No. 659,053, filed April 2, 1946, in the names of Ernest W. Stacey and Augustus D. Willhauck, and patented November 14, 1950, as Patent No. 2,529,822.

In Patent No. 2,542,217 there is disclosed an upper turret having hydraulic rate control mechanism for moving such turret in azimuth and elevation. The illustrative turret 30, which will be referred to as a lower turret and was developed for use in an airplane together with said upper turret, is provided with manually movable electric rate and space control mechanism commonly referred to as aided tracking mechanism. Barrels 52 of the guns 40 extend through sealing clips 54 of the turret 30 which is provided with a suitable number of windows, including front Windows 56 (Fig. 1), and has an adjustable gunners support 58 arranged at the lower portion of the compartment 42. The gunner enters the turret through a door 60, a bracket 62 (Figs. 1, 2, 3, 4 and 17) upon which hand grips or controls 64 are mounted being swingable, as will be hereinafter explained, to enable the gunner to assume his position shown in Fig. 1.

Rotatably mounted upon the support ring 32 is an azimuth ring 66 (Figs. 1, 2, 7, 9 and 16) provided with a circumferentially arranged series of studs 68 (Fig. 16) which are secured. to the azimuth ring and carry rollers 10 fitting in a circumferential groove 12 of the support ring. The azimuth ring 66 also carries a plurality of anti-v friction rollers 14 (Figs. 2 and 16) which engage an internal cylindrical face 16 (Fig. 16) of the support ring 32.

' The azimuth ring 66 has at its opposite sides depending extensions 13 (Figs. 7, 9 and 16) which are provided with recesses 86 for receiving bearings 82 for trunnions 84 (Fig. 7), 84a (Fig. 9), respectively of the turret, said trunnions being secured to the turret by bolts 86, 88a. Interposed between the turret 30 and the trunnion bearings 82 are spacers 88, 88a, the spacer 88 being provided with a groove for receiving portions of a sealing ring 98 which is clamped to an outside raceway of the bearing 82 by a plate 92 secured by screws 94 to one of the extensions of the azimuth ring 66. Threaded onto the outside of each of the trunnions 84, 84a is a nut 96 which is held in its adjusted position upon its associated trunnion by a lock piece 98.

The electrically powered mechanism for moving the turret 38 in azimuth and elevation is for the most part housed within and supported by the turret 30 and comprises aided tracking mechanism which is housed in a box I (Figs. and 18) and may be referred to as an aided tracking box. The aided tracking box I00 is controlled by the hand grips 64 and is constructed and arranged as disclosed in an application for United States Letters Patent Serial No. 779,472, filed October 13, 1947 in the names of Lloyd G. Miller and Ernest W. Stacey, and patented November 8, 1949, as Patent No. 2,487,256. Azimuth and elevation motors I02 (Figs. 2, 6, 7, 10 and 19), I04 (Figs. 2, 8, 18 and 19) which are screwed or otherwise secured to the turret along the left and right inside walls of said turret, as viewed in Fig. 2, are operated through selsyn transmitter and transformer controls which are well-known in the art and are disclosed in United States Letters Patent No. 1,626,824, granted May 3, 1927 on an application filed in the names of Hewlett et a1. Since selsyn remote control mechanism is well-known in the art and forms no part of the present invention, such mechanism is not described in detail herein. I

An azimuth drive for the turret 30 includes mechanism which is powered by the azimuth motor I02, and as best illustrated in Fig. 7, passes through a hollow passage I06 in the trunnion 84 and operates a vertical shaft I08 rotatable upon ball bearings H0 (Figs. 7 and 16) mounted in the extension 18 of the azimuth ring 66. The vertical shaft I08, through mechanism which will be hereinafter described, is operatively connected to a sprocket II2 (Figs. 2, 16 and 18) which meshes with a circular series of rollers I I4 (Figs. 2 and 16) carried by the support ring 32, the construction and arrangement being such that rotation of the sprocket causes rotation of the azimuth ring 66 upon the support ring.

An elevation drive of the turret 39 includes the elevation motor I04 (Figs. 2, 8 and 18) to which, through mechanism hereinafter described, is operatively connected an elevation pinion H6 which is rotatably mounted in the frame of the turret and is in meshing engagement with an arcuate rack I I8 (Figs. 8, 9 and 16). The arcuate rack H8 is arranged in concentric relation with an axis of rotation I20 of the trunnions 84, 84a and is secured by bolts I22 (Fig. 9) to the azimuth ring 66, the construction and arrangement being such that rotation of the pinion I It causes the turret 30 to move about the axis of rotation I20 with the result that the guns are moved in elevation about said axis.

Grip controls The grips 64 are pinned to a shaft I24 (Figs. 3, 4 and 18) which passes through alined bores in 'a yoke I26 (Figs. 3 and 4) a shank of which is upon the shaft I24 and in a bifurcation of the yoke I26 is a spacer portion of an elevation arm I30 (Figs. 2, 3, 4 and 18) which is operatively connected by a ball and socket I32 to the upper end of a rod I34 universally connected to a lever I36 fulcrumed upon a pin I40 threaded into the bracket 62. A bifurcated left end of the lever I35 as viewed in Fig. 3 carries pins I42 (Fig. 3) constructed and arranged to fit in a circumferential groove I44 of a collar I46 secured to a vertically arranged rod I48 (Figs. 3, 4, 5 17 and 18), the lower end of which is slidingly mounted in a bore I50 (Fig. 3) of a sleeve I66 secured to the bracket 62 and the central portion of which fits slidingly in a bore I56 of a sleeve I58 forming part of the elevation drive which will be described later. The bracket 62, which is swingable counterclockwise from its effective position shown in Fig. 2 to permit the gunner to assume the position shown in Fig. 1, has a recess I60 (Figs. 3 and 5) for receiving a depending stud I82 of a boss I64 secured to the side wall 56a and has secured to it the depending sleeve I66 fitting in a bore I52 of a boss I54 fixed to said side wall. As will be explained later, the sleeve I58 is slidingly mounted in alined bores of the bracket 62 and the stud I62 of the boss I64 respectively. The upper end of the rod I48 has formed on it a rack I68 (Figs. 5, 17 and 1s) meshing with a pinion Ilii pinned to one end of a shaft I12 (Figs. 3, 5, 10, 17 and 18) which is rotatable in the turret frame and has at its other end a gear I14 (Figs. 10, 1' and 18) meshing with a rack I16 which is pivoted by means of a pin 211 to a rod I18 and through limit stop mechanism I hereinafter described, actuates a link I82 (Figs. 2, 10 and 18) pivoted to an elevation arm I84 of the aided tracking box I00 which as above stated, is described in detail in said Patent No. 2,487,256, to actuate through elevation selsyn transmitters I86 (Figs. 2, 10 and. 19), I88 and selsyn transformers or receivers I31 gigs. 2, 8, 18 and 19), I92, the elevation motor To the lower end of the yoke I26 in which the grip carrying shaft I24 is rotatably supported is secured an arm I94 (Figs. 1, 3, 4 and 18) operatively connected through a rod I96 (Figs. 3, 4, 17 and 18) to an oifset bell crank lever I98 journaled in the bracket 62. Secured to a bifurcated portion of the bell crank lever I08 are pins 200 (Fig. 3) fitting in a groove of a collar 202 secured to the sleeve I58 through which the vertical rod I48 slides. The sleeve I58 has an enlarged upper end portion provided with a rack 284 (Figs. and 18) in driving relation with a pinion 286 (Figs. 3, 5, 1'7 and 18) secured to one end of a shaft 288 which is journaled in the turret frame and has secured to its other end a gear 2I8 (Figs. 10, 17 and 18) meshing with a rack 2 I2 of a slide 2I4 operatively connected through a link 2l6, a bell crank lever 2I8 (Figs. and 18) and a link 228 to an azimuth arm 222 of the aided tracking box I88.

It will thus be apparent that displacement of the grips 64 in azimuth about an axis 224 (Figs. 3 and 18) of the yoke I26 and in elevation about an axis 226 (Figs. 3, 4 and 18) of the shaft I24 will move the azimuth and elevation levers 222, I84 of the aided tracking box I88 and thus through mechanism disclosed in said Patent No. 2,487,256 will actuate through azimuth selsyn transmitters 228, 238 (Figs. 2, 10 and 19) and azimuth selsyn transformers or receivers 232, 234 (Figs. 2, 6, 10, 18 and 19) and azimuth motor I82.

The elevation selsyn transformers or receivers I98, I92 and the azimuth selsyn transformers or receivers 232, 234 are wired to a servo amplifier 23I (Fig. 19) and to azimuth and elevation motor generators 233, 235 which are located outside of the turret and are wired to the azimuth and elevation motors I82, I84 respectively. Power is. supplied to and from the turret 38 through suitable collector rings (not shown).

It is desirable that when the grips 64 are released they shall move automatically to neutral positions illustrated in Figs. 3 and 4. Accordingly, there is movable in bores of the bracket a slide 236 which is normally urged to the right as viewed in Figs. 3, 4 and 1'7 by a spring 248 and has a Vshaped head 242 engaging a roll 244 carried by the lever I 36. When the lever I36 is displaced from its neutral position the slide 236 yields against the action of the spring 248 and when the grips 64 are released the fork 242 acting through the roll 244 returns the lever to its neutral position.

In order automatically to centralize the azimuth drive when the grips 64 are released the bell crank lever I98 has an abutment 246 which is constantly engaged by an opposing flared end of a slide 248 mounted for reciprocation in a guideway 258 of the bracket 62 and is constantly forced upward as viewed in Fig. 3 by a spring 252. When the grips 84 are in their neutral positions in azimuth the abutment 246 and the flared end of the slide 248 are in the positions shown in Fig. 3. When the grips 84 are displaced in azimuth the slide 248 is depressed against the action of the spring 252 and after release of said grips returns the grips to their neutral positions in azimuth.

In order to enable the gunner to assume his proper position in the turret the bracket 62 is swung about an axis 254 (Fig. 3) of the rod I48 after depressing a latch or look 256 which is pivoted upon the boss I54 of the turret frame and has formed in it a hole 258 constructed and arranged to receive a stud 268 on the bracket, the latch being constantly urged upward toward the stud by a spring 262. Upon entering the turret the gunner depresses the latch 256 against the action of the spring 262 thus releasing the bracket 62 which is swung aside until said gunner reaches his seat, the bracket then being moved to and locked in its operative position shown in Figs. 3 and 4.

Azimuth hand drive The azimuth and elevation cranks 48 (Fig. 2), 48a (Figs. 1, 2, 1'7 and 18) for use in automatically charging the guns 48 respectively are also utilized by the gunner manually to move the turret in azimuth and elevation when there is no power. Such manual operation of the turret is not commonly effected for the purpose of training the guns 48 but usually for the purpose of moving the turret into a suitable position for permitting its retraction into the fuselage.

The azimuth crank 48a (Fig. 17) is rotatable on a bearing boss of a disk 218 fixed to a shaft 216 which is mounted for rotation in the turret 38. Slidable in a bore 264 of the azimuth crank 48a is a plunger 266 having at its inner end a hand button 268 which is engaged by the gunner selectively to move the plunger 266 to a charging position in one of a plurality of spaced openings 218 (only one shown) in a disk 212, or to a turret actuating position in one of a plurality of circumferential spaced recesses 282 in the periphery of the disk 218. The disk 212 is rotatably mounted upon the shaft 216 and has secured to it a sprocket 214 of charger mechanism (not shown). When the plunger 266 is in its turret actuating position shown in Fig. '17, its left end portion is in one of the recesses 282 of the disk 218 so that rotation of the crank 48a causes rotation of the shaft 216. When the plunger 266 extends into one of the openings 218 so as to cause rotation of the sprocket 214 upon rotation of the crank 480,, a notch 288 of the plunger lies opposite the periphery of the disk 218. The positioning of the plunger 266 in the crank 48a preparatory to charging of the gun and the turning of the turret is facilitated by a stop pin 284 which extends into an elongated slot 286 in the plunger.

The shaft 216 is mounted for rotation in the turret frame, which includes the compartment wall 58a, and has secured to it a sprocket 288 (Figs. 6, 1'7 and 18) which is operatively connected by a chain 298 to a sprocket 292 (Figs. 6, 15 and 18) splined to a sleeve 294 (Figs. 6 and 15) slidingly mounted upon a rod 296 secured by nuts 298 to the turret frame. The sleeve 294 is constantly urged to its idle position against a flange 388 which is secured to the right end (Fig. 15) of the rod 296, by one or more springs 362 (Fig. 15) interposed between the sprocket 292 and a flange of the sleeve 294.

The end of the sleeve 294 is provided with a plurality of teeth 384 constructed and arranged to fit in recesses in the hub 386 of a spiral gear 388 (Figs. 6, 15 and 18) which is rotatably mounted upon bearings 3I8 (Fig. 15) supported by the rod 296, the teeth and the recesses forming a clutch through which rotation of the sleeve 294 is imparted by the spiral gear 388 to a spiral gear 3I2 secured to a shaft 3I4 coupled by mechanism hereinafter described to a shaft 3I6 of the motor I82. The sleeve 294 is slid along the rod 298 into .and out of its operative position, by a shifting yoke 3I8 (Figs. 6, 15 and 18) which carries pins 328 (Fig. 15) upon which are mounted rolls 322 fitting in a circumferential groove 324 (Figs. 15 and 18) formed in the sleeve.

The shifting yoke 3I8 is operatively connected, through mechanism which will now be described, to a rod 326 (Figs. 6, 17 and 18) having a hand knob 328 which is located just inside the wall 58a of, the gunners compartment 42. The rod 326 is slidingly mounted in a packing gland 338 (Fig. 17) secured to the wall 58a of the compartment and is pivoted toythe forward end of a lever 332 (Figs. 6, 1'7 and 18) fulcrumed on a stud 334 (Figs. 6 and rrie by a brisk t ermic ar-t of the frame of the turret. The lever 332 is operatively connected by a link 336 with lever 338 (Figs. 17 and i8) fixed to the lower end of a vertical rod 343 (Fig. 6 and 17) rotatable in the turret frame. Pinned to the upper end of the red 3438 is the shifting yoke 3l8 which as above explained carries rolls 322 (Fig. fitting in the groove 324 of the sleeve 294. When the hand knob 32;; of the rod is in the position illustrated in Fig. 17, the clutch, comprising the teeth 304 (Fig. l5) and the recesses 35.3, is disengaged, the sleeve 294 being in its position illustrated in Fig. 15,

When during the failure of-electri'city, it is desirable to move the turret 3 0 in azimuth, the operator presses on the hand knob 32.8 causing it to be moved against the peeking gland 330 with the result that the sleeve 29.4 is moved to the left as viewed in Fig. 15 causing the teeth 38.4 of the sleeve to enter the recesses 306 of the hub of the spiral gear 358. Rotation of the crank 4.8a effects rotation of the spiral gear 303 and, accordingly, through mechanism hereinafter described rotation of the turret 3G in azimuth, together with the azimuth ring 55, upon the support ring 32.

In order that the turret .38 maybe manually moved in azimuth from inside the fuselage, the shaft 2'56 (Figs. 17 and 18) has fixed to itfa bevei gear 333 meshing with a bevel gear 335 secures to a shaft 33? which is rotatably mounted in bracket of the turret frame and is operated by a flexible cable (not show n) accessible from outside the turret but inside of the fuselage. The clutch formed by the teeth 3E4 of the sleeve 29 4 and the recesses 333 in the hub of the spiral gear 332 may be engaged from the outside of the turret by actuating a flexible cable (not shown which operates an offset bell crank lever 333 having a slot 34f through which passes a rear end portion of the lever 338.

The mechanism, through which the turret 30 by use of the crank 48 is manually driven inclevation from the gunners compartment .42 and also from the inside 9f the fusela e but outside of the turret, is substantially the same as the above described mechanism for driving the turret in azimuth. An elevation shifting yoke 342 (Figs. 8 and 9), which is secured to a shaft 344 (Fig. 8) rotatable in the turret frame and corresponds to the azimuth shifting yoke 318, is constructed and arranged to slide a sleeve 348 lengthwise of a rod 348 secured by a nut 350 to the turret frame, causing a clutch 352 corresponding to the clutch formed by the teeth 304 of the sleeve 234 and the recesses 306 of the hub of the spiral gear 308 selectively to be engaged or disengaged. When the clutch 352 is engaged, a spiral gear 354 rotatably mounted upon a bearing on the rod 348 drives a spiral gear 356 (Fig. 9) mounted on a shaft 358 (Fig. 8) and through mechanism hereinafter described rotatesthe turret 3G in elevation about the common axis (Figs. '7 and 9) of the trunnions 84 (Fig. 7),84a (Fig. 9).

Before moving the turret 30 in elevation it is necessary to release a -friction brake ,360 (Fig. 8) which prevents, when the power is off, the turret 33 from rotating into a position in which the barrels 5 2 of the guns 40 drop down. The vertical shaft 344 has secured to it a lever 382 universally connected to a rod 364 which is universally connected to the lower endof a lever 366 fulcrumed on a pin r368 secured-to a friction brake housing .310 forming part of the turret frame. The upper end of the lever 36!; ispivotally connected to a 1in'k3l2 having a slot 314 in which fits a pin 316 carried by the lower arm of a bell crank'lever 318 mounted upon a pm 380 secured to the turret frame. A bifurcated end of'an upper arm of the bell crank lever 318 straddles a shaft 382 of a solenoid 384 and bears against a collar 386 secured to the shaft which is normally urged to the right as viewed in Fig. 8 by a spring'hiot shown) Secured to the shaft 358 is a friction wheel 330 which is arranged in the friction brake housing 370 opposite a friction presser drum 392 having a shank 394 which is slidable toward and away from the shaft 358 but is keyed against rotation in the housing. Surrpu n'ding the shank 394 and interposed between a face of the presser drum and the housing 310 is a spring 398 which constantly urges the drum 332 toward the friction wheel 338. The shank 394 straddled by the lower arm of the bell crank lever 378 and has secured to it a collar 393 which is constantly engaged by said lever. When the curreht'is on, theshaft 382 of the solenoid 384 is retracted against the action of the spring 396 andthe spring" (not shown) of the solenoid causes the bell crank level 3'53 to be moved counterclockwise to'move the presser drum 392 away from the frictionwheel 330. When power fails or is turned off the spring 393 forces the presser 332 against the friction wheel 393. In order to'move the turret 30 manuallythrough the above mechanism, it is first necessary to release the force applied by the presser drum 332 against the friction wheel 33%]. lccord ingly, as the rod 344' is rotated to cause the clutch 352 formed by the sleeve 348 and the hub of the spiral gear 354 to be engaged, the pr'sserldrum 332 is moved to the rightas viewed in Fig. 8 to release the shaft 358 for movement in response tol'moveme'nt of the spiral gear-354.

as ez iplained in said Patent No. 2,487,256 when the azimuth lever 2212 is displaced a selected num ber 9f degrees f 1 01l1 its neutral position the turret starts to rotate in azimuth, accelerating rapidly to its nasimum rate. A feed-back (not shown) Qss air-A l era i e lu iihsh ra e quickly to reduce the rate to a'level determined by a ai w i q me anism w iqbsin the aided tracf ing mechanism and is active, as

\ long las the grips 16,4 are displaced, to maintain the'rate at a level determined by the assent of displacement of the grips. As abov e explained, the azimuth motor 152 is controlled by the azimuth selsyn transformers or receivers 232, 234 which are responsive to movement of the selsyn transmitters 228, 23s operated by the aided tracking bog; lflil. Theshaft3l4 (Figs. 6, 1 5 and 18) is'coupledto a shaft 4% (Figs. 6, 7 and-l8 which isforfned'integral with a worm 434 and is secured by a coupling 438 (Fig. 6) rotatable in bearings 432, for movement with the shaft 316 (Figs: 6 and 18) of the motor 132. The worm 404 meshes with a worm gear 488 (Figs. 6, -'7 and 18) splined on a shaft 4H1 rotatably mounted in bearings 412 (Fig. '7) supported by the turret frame and having a spacer 4l 3 upon which is rotatable a hub'o'f'a gear-carrier 414 mounted in bearings 4l6 supportedby the turret frame. The shaft 410' is boltedto acoupling 443 which. is in splined driving relation with a shaft 428 (Figs. 7 and 18) mounted in bearings 422 supported in the -hollow passage Hit of the trunnion 84. The shaft 420, thecoupling 4t8 and theshaft 4w together form, in effect, a-single shaft. The outerend of the shaft 428 has fixed to it a-bevel gear'422 meshing with a bevel gear 424 keyed to the lower end of the vertical shaft I08 which is journaled for rotation in the bearings IIO (Figs. '7 and 16). Fixed to the upper end of the shaft I08 is a pinion 428 (Figs. 16 and 18) meshing with a pinion 430 formed integral with a sleeve 432 (Fig. 16) rotatable upon a bearing shaft 434 which is carried by a yoke 436 (Figs. 2 and 16) swiveled upon a tube 438 fixed to and in effect forming part of the azimuth ring 66. Secured to the sleeve 432 is the sprocket II2 (Figs. 2, 16 and 18) meshing with the rolls II4 (Figs. 2 and 16) which are mounted on upstanding pins 440 (Fig. 16) carried by the support ring 32. Rotatably mounted upon heads 442 of the pins 440 are rolls 444 (Figs.2 and 16) which fit in a cam groove 446 (Fig. 2) of a cam plate 448 pivoted upon the upper end of the shaft 434, the construction and arrangement being such that the cam plate retains the sprocket I I2 in driving relation with the rolls I I4 when the vertical drive shaft I08 is rotated thereby effecting rotation of the sprocket and accordingly movement of the turret in azimuth about an axis 450 of the azimuth ring. By mounting the yoke 436 for swinging movement as above described it will be clear that even though the azimuth ring 66 should become distorted as it sometimes does due to changes in the temperature and flexing of the fuselage upon which the azimuth ring is mounted, the sprocket IIZ will at all times be held in its proper driving relation with the rolls I I4 in order effectively to drive the turret in azimuth.

Elevation drive The elevation motor I04 is provided with a shaft 452 (Fig. 8) operatively connected through a coupling 454 mounted in a ball bearing 456 supported by a turret frame, with a shaft 455 formed integral with a worm 458. The right end of the shaft 455 as viewed in Fig. 8 is coupled to the. shaft 358 formed integral with the helical gear 458 and is rotatably mounted in a ball bearing 460 carried by the turret frame and which has secured to it the above described friction wheel 390.

The worm 458 meshes with a worm gear 462 (Figs. .8, 9 and 19) secured to a shaft 45I (Figs. 9 and 18) which is rotatably mounted upon bearings 453 (Fig. 9) mounted in the turret frame and has secured to it a small gear 455 in driving relation with a large gear 451 secured to a shaft 459. The shaft 459 is journaled in the turret frame and has secured to it the above-mentioned pinion II6 which meshes with the arcuate rack II8 which, as above described, is secured'to the azimuth ring 66.

The turret 30 may be moved continuously in either direction in azimuth. Mechanism is provided, however, for limiting movement of the turret 30 in positive or negative elevation, movement of the turret together with its guns 40 in negative elevation being automatically stopped when the guns are lowered to positions in which the barrels 52 of the guns are approximately parallel to the axis of rotation 450 of the azimuth ring 66. Because of the shape of the fuselage and the arrangement of the turret in its projected position in the fuselage, the extent to which the guns may be raised depends upon the position of the turret in azimuth. Accordingly, movement of the turret 30 together with the guns 40 in positive elevation is limited by mechanism which automatically causes the elevation lever I84 of the aided tracking box I00 to move to neutral Position when the guns are predetermined distances from the fuselage. Because of the great weight of the armed turret, there is also provided mechanism for varying the time at which the guns start to stop in elevation in accordance with the speed of the turret -in elevation, thereby insuring against excessive strains being imparted to the trunnions 84, 84a. Fire interrupters or cut-outs are also provided to prevent the firing of the guns when the guns point at portions of the airplane.

As above explained, the rod I18 (Figs. 10, 11 and 18) which is operatively connected to the hand grips 64, is operatively connected to the elevation lever I84 of the elevation rate control box I00 through the limitstop mechanism I80. Pivotally connected to the upper end of the rod I18 is a multi-arm lever 464 (Figs. 10, 11, 12, 13 and 18) pivoted upon a fulcrum pin 466 secured to the turret frame.

The rear end of the multi-arm lever 464 is pivotally connected through a link 412 to a lever or arm 414 pivotally mounted upon a floating or shiftable fulcrum pin 416 operatively connected to the lower end of a rod 418 which as will be explained later, is shifted vertically in response to movement in elevation of the turret 30 in order to limit through mechanism hereinafter described, movement of the turret in positive and negative elevation. The front end of the lever 414 is operatively connected through a link 480 to a bell crank lever 482 (Figs. 10 and 18) which is fulcrumed upon a pin 484 (Fig. 10) secured to the turret frame and is pivoted at its upper end to the link I82 pivoted to the elevation lever I84 of the aided tracking box I 00. p

The multi-arm lever 464 'is operatively connected through a link 486 to the forward end of a lever 488 fulcrumed upon a stud 490 which is carried by an arm 492 pivoted upon a pin 493 secured to the' turret frame. mounted on it a roll or cam follower 494 (Figs/'7, 12 and 18) fitting in a circumferential cam groove 496 formed in a cam 498. The cam 498, through mechanism which will be hereinafter described,

is secured for rotation upon a vertical shaft 500 secured to the upper end of a drum or cylinder 502 forming part of a firing cut-out mechanism 504 (Figs. 6 and 12) and having secured to'it a depending shaft 506, said shafts being mounted "-in bearings'508, 5I0 (Fig. 12) respectively of the turret frame and rotated together with the drum at the same rate that the turret moves in azimuth, the construction and arrangement being such that the cam 498 together with the drum rotates degree for degree with the turret. To the rear end of the lever 488 ispivotally connected a link 5| 2, the lower'end of which is pivotally connected to a cam, slide or plate 5l4 fitting in a guideway 5I6 (Figs. 11 and 13) of the turret frame, the

'slide being permitted to'move lengthwise but not laterally of'the guideway. Resting against the slide 5I4 is a cam or plate 5I8, the lower portion of which is pivotally connected to the mu ti-arm lever 464 by a link'520. The slide 5I4 is held in the guideway 5I6 and'the plate 5I8 is held pressed against the slide by a retaining plate 5I5 which is' secured to the turret frame by screws 5 I 1. The slide 5 I 4 has formed in it a slot or camway 522 (Figs. 11, 13 and 18) which is straight and is vertically disposed from its lower end to a shoulder 524, saidslot then being curved to the left as viewed in Fig. 11. The plate 5| 8 is provided with a slot or camway 526, a straight vertical portion of which is in register with the vertical portion of the slot 522 of the slide 514 The stud 490 has 

